A technique for fabricating a three-dimensional periodic structure having a period of about 1 μm or less in a material has a broad range of possible application in the fields of optical technologies and electronic technologies. However, its fabrication method is not developed yet, and a three-dimensional periodic structure with a period of about 1 μm or less has not been realized up to now. Among techniques which have been examined, the following two are main ones: (1) a method in which holes are formed in three directions by dry etching, as shown in FIG. 54, (E. Yablonovitch, “Photonic band-gap structures”, J. Opt. Soc. Am. B, vol, 10, no.2. pp. 283-295, 1993); and (2) a method in which substrates with parallel square rods on them are opposed and bonded to each other, one of the substrates is removed by selective etching, and another substrate is opposed and bonded again to repeat the operation, as shown in FIG. 55, (S. Noda, N. Yamamoto, and A. Sasaki, “New realization method for three-dimensional photonic crystal in optical wavelength region”, Jpn. J. Appl. Phys., vol. 35, pp. L909-L912, 1996). Up to now, these two ideas are not realized int eh case that the period is about 1 μm or less and the number of periods is five or more.
In the above-mentioned method (1), it is disadvantageous that processing of more than three or four periods is impossible. In the above-mentioned method (2), reproducibility and productivity are low, since it depends on handicraft processes with low controllability such as selective chemical etching and bonding many times.
The present invention is completed to solve the above-described problems of the conventional techniques, and its object is to provide a three-dimensional structure having a period of about 1 μm or less, to provide parts and devices to which that structure is applied, and to provide their fabrication method.